An image printing method employing an ink-jet system is a method to print in such a manner that minute ink droplets are jetted from ink-jet recording heads to adhere to targeted recording media. Ink-jet systems exhibit advantages since its mechanism is relatively simple and less expensive in cost and further, it is possible to form highly detailed and high quality images.
By utilizing the above advantages of the ink-jet systems, developed has been image printing onto textiles, so-called ink-jet textile printing. The ink-jet textile printing, differing from conventional textile printing, does not require formation of plates and exhibits features such as quick formation of images of excellent gradation. In addition, the ink-jet textile printing method may be described as an excellent image forming method which also exhibits environmental protection such as minimal liquid waste compared to conventional methods since only enough ink is consumed to form the image.
Generally, in the dyeing industry, a large amount of water is consumed in each process, and as a result, a large amount of effluent is discharged. For the disposal and treatment of the above effluent, a great expense is incurred and it is essential to secure a steady and high volume of water resources. Consequently, demanded has been an ink-jet textile printing method capable of reducing the load for the treatment and disposal of the effluent, namely an ink jet textile printing method which exhibits excellent washing properties.
Particularly, in the case of hydrophobic synthetic fibers such as polyester, commonly is performed dyeing employing water-insoluble disperse dyes. In disperse dye ink which is prepared by dispersing disperse dyes together with dispersing agents, in order to remove the dispersing agents which are unnecessary after color development as well as disperse dyes which are not fixed onto the fibers, a washing process is required. Washing properties during the above washing process include the following; unnecessary components (such as pastes or dispersing agents) for final products, which are incorporated in ink or pre-treatment materials are easily removed, the amount of sludge is as small as possible, or components which result in stain of dyed products are easily removed.
In the ink-jet system, since the viscosity of employed inks is lower than that of color pastes employed in conventional textile dyeing, it is necessary to minimize ink bleeding on the textile, whereby the resulting washing properties are greatly influenced by the bleeding resistant methods.
For example, proposed is a textile dyeing method in which a pretreatment is performed employing pastes, water-soluble salts, or minute inorganic particles (refer, for example, to Patent Document 1). In the above method, a large amount of sludge is formed during washing. As a result, it is accepted fact that washing capability is not satisfactory.
Further, disclosed are a method in which the effluent treating load is lowered by controlling the moisture content of textiles to enhance the degree of exhaustion (refer, for example, to Patent Document 2) and a method in which washing is omitted or shortened by employing specific dispersing agents (refer, for example to Patent Document 3). However, any of these proposed methods do not thoroughly improve the washing properties, and the resulting effects are limited.
In view of the foregoing, demanded has been development of ink-jet textile printing methods which result in no formation of sludge and exhibits excellent washing properties.    (Patent Document 1) Japanese Patent Publication for Public Inspection (hereinafter referred to as JP-A) No. 61-55277    (Patent Document 2) JP-A No. 5-295675    (Patent Document 3) JP-A No. 10-114866